(*The Pauli deformation according to description on p  .1050 .  It is shown where from and where to 
there is a flow of the electron density at the internuclear distance  R .  
          In the first case 
(two helium atoms) the density distribution is expulsed from the internuclear region 
(visible as a valley) and put on the nuclei  (maxima there) . 
In the second case  (two hydrogen atoms) the opposite happens.*) 
R = 4. 
pi = 3.141592532
a = (Sqrt[(1/pi)]) (E^(-(Sqrt[(x^2) + (y^2)])))
b = (Sqrt[(1/pi)]) (E^(-(Sqrt[(((x - R))^2) + (y^2)])))
S = (1 + R + ((R^2)/3)) (E^(-R))
lbd = 1. 
N1 = (1/(Sqrt[1 + (lbd^2) + 2 lbd S]))
wsp = ((lbd + S)/(1 + lbd S))
N2 = (1/(Sqrt[1 + (wsp^2) - 2 wsp S]))
fi1 = N1 (a + lbd b)
fi2 = N2 (wsp a - b)
dHe2 = 2 ((fi1^2) + (fi2^2)) - 2 (a^2) - 2 (b^2)
Plot3D[dHe2, {x, -2. , 6. }, {y, -2. , 2. }, 
      PlotPoints -> 31]
dH2 = 2 (fi1^2) - (a^2) - (b^2)
Plot3D[dH2, {x, -2. , 6. }, {y, -2. , 2. }, 
      PlotPoints -> 31]